Virus-can't delete it

i have a big problem with my brother s tablet. he is only 6 so he does not know what he is installing bla bla bla. he had some viruses before on his tablet but a factory reset did all the job. now the problem is very serious. he installed something( i dont know what) and the downloaded app made more apps(smth like that). i did factory reset.nothing.the app is still installed but has no administrator rights and i cant find it either under app manager. the tablet is a 10.1 note and its pretty old and i cant enter the safe mode.i am trying to get into odin mode so i can flash it but after i get the message with warning and to continue with volume down and stuff at that moment when i realese either power button or volume down it just goes and normally starts after 1 second. so im practically unable to factory reset because the virus is still there with no administrative rights. i did install 360 antivirus and lookout.both found 5 or 6 apps with malware.i did uninstall them with lookout (nothing happend) and stopped the procceses with 360 antivirus,still no help. + i have on my main page an app called "sexy" which im unable to delete.i cant find it either on settings so im unable to delete it..if someone could help me it would be great and sorry for my english i hope you understood me

i have a big problem with my brother s tablet. he is only 6 so he does not know what he is installing bla bla bla. he had some viruses before on his tablet but a factory reset did all the job. now the problem is very serious. he installed something( i dont know what) and the downloaded app made more apps(smth like that). i did factory reset.nothing.the app is still installed but has no administrator rights and i cant find it either under app manager. the tablet is a 10.1 note and its pretty old and i cant enter the safe mode.i am trying to get into odin mode so i can flash it but after i get the message with warning and to continue with volume down and stuff at that moment when i realese either power button or volume down it just goes and normally starts after 1 second. so im practically unable to factory reset because the virus is still there with no administrative rights. i did install 360 antivirus and lookout.both found 5 or 6 apps with malware.i did uninstall them with lookout (nothing happend) and stopped the procceses with 360 antivirus,still no help. + i have on my main page an app called "sexy" which im unable to delete.i cant find it either on settings so im unable to delete it..if someone could help me it would be great and sorry for my english i hope you understood me

Perform another factory reset and format the SD card (internal memory). You'll lose all the data on it, so backup anything that may be important. There might be something saved on the internal storage which is redownloading files to your tablet.

Perform another factory reset and format the SD card (internal memory). You'll lose all the data on it, so backup anything that may be important. There might be something saved on the internal storage which is redownloading files to your tablet.